The present disclosure relates to a radio frequency (RF) switch.
In accordance with the development of wireless communications technology, various communications standards have been developed simultaneously. In addition, in accordance with the miniaturization of wireless communications modules and improvements in the performance of portable communications terminals, the need for individual portable communications terminals to conform to a plurality of communications standards has become apparent. Therefore, the amount of frequency bands that an individual portable communications terminal should be operable with has increased.
That is, existing second-generation (2G) and third-generation (3G) communications technologies have been supplemented with new communications technologies, such that portable communications terminals using fourth-generation (4G) communications schemes such as Long Term Evolution (LTE) have been developed. In addition, in the area of Wi-Fi communications, portable communications terminals have been implemented with the ability to operate with the IEEE 802.11ac standard in addition to the existing IEEE 802.11b/g/n to enhance marketability thereof.
In accordance with this trend, a front end module has been disposed in front of a transceiver to be integrated therewith. In this case, a switch block supporting both transmitting and receiving modes is present.
The switch block should maintain characteristics of a transmitter and a receiver as much as possible. Particularly, the switch block should have low insertion loss and a high P1 dB levels in the transmitting mode and should have low noise in the receiving mode. In addition, in the transmitting mode, a switch on a receiver side may be unintentionally turned on due to a very large signal. This operation may lower a P1 dB level of a switch of the transmitter and deteriorate isolation characteristics between the transmitter and the receiver.
Therefore, a switch structure appropriate for operating with high level signals is required, and there is a need to improve performance of a switch in the transmitting and receiving modes using such a switching structure.
The following Related Art Document (Patent Document 1), related to a RF switching circuit and a control method thereof, discloses a switch capable of preventing an operational change thereof even when a high level signal is applied thereto by generating a predetermined negative voltage and applying drain and source voltages of a switch as opposed to a gate. However, Patent Document 1 does not disclose a technology of decreasing a magnitude of a signal input to a gate using a switching device coupled between the gate and a source or between the gate and a drain to decrease a voltage difference between a source voltage and a gate voltage or between a drain voltage and the gate voltage.